Method of improving the performance of submerged oxygen injectors

Abstract

In the injection of oxygen through a refractory lined wall into a molten metal, for example, pig iron, the injected oxygen is surrounded by a stream of a protective fluid to diminish erosion of the refractory lining; the velocities of the oxygen and protective fluid are selected to minimize eddying of the oxygen into the protective fluid so that the protective fluid retains its effectiveness for a greater distance from the injector whereby greater protection is provided to the injector and the refractory.

We claim: 
     
       1. In a method of injecting oxygen into a bath of molten metal, in the refining of said metal, in which the oxygen is injected in a stream into the molten metal from below the upper surface thereof and in which the injected oxygen is surrounded by a simultaneously injected stream of protective fluid, the improvement wherein the velocity of the stream of protective fluid is about 0.5 to 1.5 times the velocity of the oxygen stream at the point of injection, whereby turbulence between the streams is substantially minimized. 
     
     
       2. In a method of injecting oxygen into a bath of molten metal, in the refining of the metal, in which the oxygen is injected in a stream into the molten metal from below the upper surface thereof and in which the stream of oxygen is surrounded by a stream of a hydrocarbon, the improvement wherein the velocity of the stream of hydrocarbon is about 0.5 to 1.5 times the velocity of the oxygen stream at the point of injection, and said hydrocarbon stream scavenges oxygen which eddys into the hydrocarbon stream to prevent the oxygen and molten metal reacting, with a minimum of turbulence between the streams. 
     
     
       3. A method according to claim 1, wherein said metal is pig iron and said fluid is selected from the group consisting of N 2 , SO 2 , H 2  O, Ar, CO 2  and a hydrocarbon. 
     
     
       4. A method according to claim 1 wherein said metal is pig iron and said fluid is a hydrocarbon. 
     
     
       5. A method according to claim 1, wherein said molten metal is selected from the group consisting of lead, tin, nickel, cobalt and copper.